Adobe InDesign is a document design software in the Creative Cloud lineup. It’s especially good for print documents, given the options with bleed, margins, color, and placement of elements. A similar program is Microsoft Publisher, which has a lower learning curve than InDesign does. 

InDesign has specific features that make it good for documents with many pages, but it can just as easily be used for a one-page project like a flyer. 
UIUC offers Adobe Creative Cloud for free for its students, which you can download from the Illinois Webstore. It can take up to a day for Campus IT to activate your Adobe License, at which time you can download any of the Creative Cloud program. There is a webpage with instructions on how to activate your access to Creative Cloud as well.